struts2连接MySQL出现HTTP Status 500 问题
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发布时间：2022-04-10 20:25
共5个回答
懂视网
时间：2022-04-11 00:47
1.1在pom.xml中导入相关依赖
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.ht</groupId> <artifactId>T224_struts</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>T224_struts Maven Webapp</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.apache.struts</groupId> <artifactId>struts2-core</artifactId> <version>2.5.13</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.2.1-b03</version> <scope>provided</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.44</version> </dependency> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> <!-- 5.4、tomcat-jsp-api --> <dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-jsp-api</artifactId> <version>8.0.47</version> </dependency> </dependencies> <build> <finalName>T224_struts</finalName> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.7.0</version> <configuration> <source>1.8</source> <target>1.8</target> <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> </build> </project>
二：导入分页相关的通用pageBean类，z.tld，并且配置web.xml
2.1 导入pageBean类
package com.crud.tag;
import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import com.crud.util.PageBean;
/**
* 分页通用类
* @author Administrator
*/
public class PageTag extends BodyTagSupport {
private static final long serialVersionUID = 1L;
private PageBean pageBean;
public PageBean getPageBean() {
return pageBean;
}
public void setPageBean(PageBean pageBean) {
this.pageBean = pageBean;
}
@Override
public int doStartTag() throws JspException {
JspWriter out = pageContext.getOut();
try {
out.print(toHTML());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return super.doStartTag();
}
private String toHTML() {
StringBuffer sb = new StringBuffer();
/*
* 拼接向后台提交数据的form表单
* 注意：拼接的form表单中的page参数是变化的，所以不需要保留上一次请求的值
*/
sb.append("<form id=‘pageBeanForm‘ action=‘"+pageBean.getUrl()+"‘ method=‘post‘>");
sb.append("<input type=‘hidden‘ name=‘page‘>");
Map<String, String[]> parameterMap = pageBean.getParameterMap();
if(parameterMap != null && parameterMap.size() > 0) {
Set<Entry<String, String[]>> entrySet = parameterMap.entrySet();
for (Entry<String, String[]> entry : entrySet) {
if(!"page".equals(entry.getKey())) {
String[] values = entry.getValue();
for (String val : values) {
sb.append("<input type=‘hidden‘ name=‘"+entry.getKey()+"‘ value=‘"+val+"‘>");
}
}
}
}
sb.append("</form>");
/*
* 展示的分页条
*/
sb.append("<div style=‘text-align: right; font-size: 12px;‘>");
sb.append("每页"+pageBean.getRows()+"条，共"+pageBean.getTotal()+"条，第"+pageBean.getPage()+"页，共"+pageBean.getMaxPage()+"页 <a href=‘javascript:gotoPage(1)‘>首页</a> <a");
sb.append(" href=‘javascript:gotoPage("+pageBean.previousPage()+")‘>上一页</a> <a");
sb.append(" href=‘javascript:gotoPage("+pageBean.nextPage()+")‘>下一页</a> <a");
sb.append(" href=‘javascript:gotoPage("+pageBean.getMaxPage()+")‘>尾页</a> <input type=‘text‘");
sb.append(" id=‘skipPage‘");
sb.append(" style=‘text-align: center; font-size: 12px; width: 50px;‘> <a");
sb.append(" href=‘javascript:skipPage()‘>Go</a>");
sb.append("</div>");
/*
* 给分页条添加与后台交互的js代码
*/
sb.append("<script type=‘text/javascript‘>");
sb.append(" function gotoPage(page) {");
sb.append(" document.getElementById(‘pageBeanForm‘).page.value = page;");
sb.append(" document.getElementById(‘pageBeanForm‘).submit();");
sb.append(" }");
sb.append(" function skipPage() {");
sb.append(" var page = document.getElementById(‘skipPage‘).value;");
sb.append(" if(!page || isNaN(page) || parseInt(page)<1 || parseInt(page)>"+pageBean.getMaxPage()+"){");
sb.append(" alert(‘请输入1~N的数字‘);");
sb.append(" return;");
sb.append(" }");
sb.append(" gotoPage(page);");
sb.append(" }");
sb.append("</script>");
return sb.toString();
}
}
2.2 z.tld文件
<?xml version="1.0" encoding="UTF-8" ?> <taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0"> <description>zking 1.1 core library</description> <display-name>zking core</display-name> <tlib-version>1.1</tlib-version> <short-name>z</short-name> <uri>/zking</uri> <tag> <name>page</name> <tag-class>com.crud.tag.PageTag</tag-class> <body-content>JSP</body-content> <attribute> <name>pageBean</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
2.3 配置web.xml
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1"> <display-name>Archetype Created Web Application</display-name> <filter> <filter-name>encodingFiter</filter-name> <filter-class>com.crud.util.EncodingFiter</filter-class> </filter> <filter-mapping> <filter-name>encodingFiter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter> <filter-name>struts</filter-name> <!-- 相对于中央控制器，过滤请求 --> <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts</filter-name> <url-pattern>*.action</url-pattern> </filter-mapping> </web-app>
三：在Mysql中设计数据库
3.1 在项目中配置与mysql数据库连接
数据库用户名和密码是不一样的看你们自己怎么设置的
四：编写Dao层去访问数据库
package com.crud.dao;
import java.sql.SQLException;
import java.util.List;
import com.crud.entity.Class;
import com.crud.util.BaseDao;
import com.crud.util.EntityBaseDao;
import com.crud.util.PageBean;
import com.crud.util.StringUtils;
/**
* 班级dao方法类
* @author Administrator
*/
public class ClassDao extends EntityBaseDao<Class>{
/**
* 查询分页方法，查询数据公用方法
* @param c
* @param paBean
* @return
* @throws InstantiationException
* @throws IllegalAccessException
* @throws SQLException
*/
public List<Class> list(Class c,PageBean paBean) throws InstantiationException, IllegalAccessException, SQLException{
String sql="select * from struts_class where true ";
String classname=c.getClassname();
int cid=c.getCid();
if (cid!=0) {
sql +=" and cid = "+cid;
}
if (StringUtils.isNotBlank(classname)) {
sql+=" and classname like ‘%"+classname+"%‘";
}
return super.executeQuery(sql,paBean,Class.class);
}
/**
* 新增方法
* @param c
* @return
* @throws NoSuchFieldException
* @throws SecurityException
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws SQLException
*/
public int add(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException {
String sql="insert into struts_class values(?,?,?)";
return super.executeUpdate(sql, new String[] {"classname","cname","upload"},c);
}
/**
* 删除方法
* @param c
* @return
* @throws NoSuchFieldException
* @throws SecurityException
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws SQLException
*/
public int del(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException {
String sql="delete from struts_class where cid=?";
return super.executeUpdate(sql, new String[] {"cid"},c);
}
/**
* 修改方法
* @param c
* @return
* @throws NoSuchFieldException
* @throws SecurityException
* @throws IllegalArgumentException
* @throws IllegalAccessException
* @throws SQLException
*/
public int edit(Class c) throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException, SQLException {
String sql="update struts_class set classname=?,cname=?,upload=? where cid=?";
return super.executeUpdate(sql, new String[] {"cid","classname","cname","upload"},c);
}
}
五：编写web层去调用dao层的方法返回数据给前台
ClassAction 类
package com.crud.web;
import java.sql.SQLException;
import java.util.List;
import com.crud.dao.ClassDao;
import com.crud.entity.Class;
import com.crud.util.PageBean;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
/**
* 班级web层
* @author Administrator
*/
public class ClassAction extends BaseAction implements ModelDriven<Class>{
private ClassDao cldao=new ClassDao();
private Class cls=new Class();
public String list() {
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
try {
List<Class> list = this.cldao.list(cls, pageBean);
request.setAttribute("mylist", list);
request.setAttribute("pageBean", pageBean);
} catch (InstantiationException | IllegalAccessException | SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return "list";
}
/**
* 跳转新增修改页面的公用方法
* @return
* @throws SQLException
* @throws IllegalAccessException
* @throws InstantiationException
*/
public String preSave() throws InstantiationException, IllegalAccessException, SQLException {
if (cls.getCid()!=0) {
Class cl = this.cldao.list(cls, null).get(0);
request.setAttribute("cls",cl);
}
return "preSave";
}
/**
* 新增
* @return
*/
public String add() {
try {
result = this.cldao.add(cls);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return "toList";
}
/**
* 删除
* @return
*/
public String del() {
try {
this.cldao.del(cls);
} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
| SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return "toList";
}
/**
* 修改
* @return
*/
public String edit() {
try {
this.cldao.edit(cls);
} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
| SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return "toList";
}
@Override
public Class getModel() {
// TODO Auto-generated method stub
return null;
}
}
这里实现了一个BaseAction 类
package com.crud.web;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
/**
* 每一个开发的子控制器要用的属性都定义在通用的action中。
* @author Administrator
*
*/
public class BaseAction implements ServletRequestAware, ServletResponseAware{
/**
* 为了传值使用
*/
protected HttpServletResponse response;
protected HttpServletRequest request;
protected HttpSession session;
protected ServletContext application;
/**
* 为了配置跳转页面所用
*/
protected final static String SUCCESS = "success";
protected final static String FAIL = "fail";
protected final static String LIST = "list";
protected final static String ADD = "add";
protected final static String EDIT = "edit";
protected final static String DETAIL = "detail";
/**
* 具体传值字段 后端向jsp页面传值所用字段
*/
protected Object result;
protected Object msg;
protected int code;
public Object getResult() {
return result;
}
public Object getMsg() {
return msg;
}
public int getCode() {
return code;
}
@Override
public void setServletResponse(HttpServletResponse arg0) {
this.response = arg0;
}
@Override
public void setServletRequest(HttpServletRequest arg0) {
this.request = arg0;
this.session = arg0.getSession();
this.application = arg0.getServletContext();
}
}
六：配置struts_sy.xml文件
<!-- *代表你要调用的方法 -->
<action name="/cls_*" class="com.crud.web.ClassAction" method="{1}">
<result name="list">/clsList.jsp</result>
<result name="preSave">/clsupdate.jsp</result>
<result name="toList" type="redirectAction">/cls_list</result>
</action>
七：连接前端显示数据并且调用实现效果
ClsList.jsp(显示数据并且调用Crud)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="z" uri="/zking" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>班级</h2><br>
<form action="${pageContext.request.contextPath }/sy/cls_list.action" method="post">
班级名：<input type="text" name="classname">
<input type="submit" value="确定">
</form>
<a href="${pageContext.request.contextPath }/sy/cls_preSave.action">新增</a>
<table border="1" width="100%">
<tr>
<td>编号</td>
<td>班级名</td>
<td>学生名</td>
<td>图片</td>
<td>操作</td>
</tr>
<c:forEach items="${mylist }" var="c">
<tr>
<td>${c.cid }</td>
<td>${c.classname }</td>
<td>${c.cname}</td>
<td>${c.upload }</td>
<td>
<a href="${pageContext.request.contextPath }/sy/cls_preSave.action?cid=${c.cid}">修改</a>
<a href="${pageContext.request.contextPath }/sy/cls_del.action?cid=${c.cid}">删除</a>
<a href="${pageContext.request.contextPath }/sy/cls_upload.action?cid=${c.cid}">图片上传</a>
</td>
</tr>
</c:forEach>
</table>
<z:page pageBean="${pageBean }"></z:page>
</body>
</html>
Clsupdate.jsp(新增与修改公用界面)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="${pageContext.request.contextPath}${cls.classname ==null ? ‘/sy/cls_add.action‘ :‘/sy/cls_edit.action‘}" method="post">
cid:<input type="text" name="cid" value="${cls.cid}"><br>
classname:<input type="text" name="classname" value="${cls.classname }"><br>
cname:<input type="text" name="cname" value="${cls.cname }"><br>
upload:<input type="text" name="upload" value="${cls.upload }"><br>
<input type="submit" value="提交">
</form>
</body>
</html>
最后：展示效果
谢谢观看！今天的分享到此结束！
Struts2连接Mysql的Crud使用
标签：lock 并且 unit sch filter sea == Stub uri
热心网友
时间：2022-04-10 21:55
你说的错误在 st = (Statement) con.createStatement(); 搞错了，上面都说了调用action函数则出错：function.insert.execute(insert.java:23)，执行插入的时候错了。语法错误，没试过插入会不会返回插入数据的条数，可以去掉试试。excute执行方法不止一个好像。错在int count = st.executeUpdate(sql); 你用debug模式运行下，打断点试试。追问那么数据库连接函数该写哪呢？Action函数的内容的*有哪些？我其实没有一点JavaWeb基础，但是老师要求做一个小实验，要求利用struts2写个能对数据库进行增删查等操作的小程序。
追答这个很简单啊，你应该知道Action,po,service,这些吧。你可以去查一下java的JDBC部分代码怎么写，而，service，action就是方法的调用而已啊，action中定义一个service的实体，这样就可以调用service里的方法了，service里面定义一个的实体，service中不就可以调用中的方法吗，再和数据库交互，中写的就是jdbc的代码。你要是不会就加我1169095671，百度知道是学不到很具体的东西的。
热心网友
时间：2022-04-10 23:13
description The server encountered an internal error () that
prevented it from fulfilling this request.
exception
java.lang.NullPointerException
function.insert.execute(insert.java:23)
热心网友
时间：2022-04-11 00:47
热心网友
时间：2022-04-11 02:39
